Kinetics of human hemopoietic cells after in vivo administration of granulocyte-macrophage colony-stimulating factor.

The kinetic changes induced by granulocyte-macrophage colony-stimulating factor (GM-CSF) on hemopoietic cells were assessed in physiological conditions by administering GM-CSF (8 micrograms/kg per d) for 3 d to nine patients with solid tumors and normal bone marrow (BM), before chemotherapy. GM-CSF increased the number of circulating granulocytes and monocytes; platelets, erythrocytes, lymphocyte number, and subsets were unmodified. GM-CSF increased the percentage of BM S phase BFU-E (from 32 +/- 7 to 79 +/- 16%), day 14 colony-forming unit granulocyte-macrophage (CFU-GM) (from 43 +/- 20 to 82 +/- 11%) and day 7 CFU-GM (from 41 +/- 14 to 56 +/- 20%). The percentage of BM myeloblasts, promyelocytes, and myelocytes in S phase increased from 26 +/- 14 to 41 +/- 6%, and that of erythroblasts increased from 25 +/- 12 to 30 +/- 12%. This suggests that GM-CSF activates both erythroid and granulomonopoietic progenitors but that, among the morphologically recognizable BM precursors, only the granulomonopoietic lineage is a direct target of the molecule. GM-CSF increased the birth rate of cycling cells from 1.3 to 3.4 cells %/h and decreased the duration of the S phase from 14.3 to 9.1 h and the cell cycle time from 86 to 26 h. After treatment discontinuation, the number of circulating granulocytes and monocytes rapidly fell. The proportion of S phase BM cells dropped to values lower than pretreatment levels, suggesting a period of relative refractoriness to cell cycle-active antineoplastic agents.

Phosphotyrosine antibodies identify the p210c-abl tyrosine kinase and proteins phosphorylated on tyrosine in human chronic myelogenous leukemia cells.

Antibodies against phosphotyrosine are a powerful tool with which to identify proteins phosphorylated on tyrosine residues, such as viral oncogene-encoded transforming proteins and their cellular protein substrates. Probed on human leukemia cell lines, phosphotyrosine antibodies recognized a 210,000-molecular-weight protein (p210) in K562 cells, a cell line derived from a Philadelphia (Ph)'-positive chronic myelogenous leukemia (CML), but recognized no protein in control Ph'-negative non-CML leukemia cells. The p210 protein was also recognized by antisera against v-abl-encoded polypeptides and displayed kinase activity, phosphorylating itself on tyrosine, in an immunocomplex kinase assay. These data are consistent with reported findings of the expression of a recombined bcr-abl gene in Ph'-positive CML cells, leading to the synthesis of an altered p210c-abl protein endowed with tyrosine kinase activity. Phosphotyrosine antibodies also detected the expression of the p210c-abl protein in fresh bone marrow cells harvested from CML patients in blast crisis. Besides the p210c-abl protein kinase, phosphotyrosine antibodies recognized other proteins with molecular weights of 110,000, 68,000, and 36,000 (p110, p68, and p36) in K562 cells. When [gamma-32P]ATP was added to nonionic detergent-extracted cells, these proteins became phosphorylated on tyrosine, as confirmed by phosphoamino acid analysis. A comparison with fibroblasts transformed by the v-abl, v-src, and v-fps oncogenes suggested the identity of the p36 protein with the common 36-kilodalton protein substrate of viral oncogene-encoded tyrosine kinases. Enhanced tyrosine phosphorylation of cellular proteins is thus a feature shared by cells transformed by v-abl and cells expressing a rearranged bcr-abl gene.

Insensitivity of chronic myeloid leukemia cells to inhibition of growth by prostaglandin E1.

The influence of E prostaglandins on the in vitro growth of chronic myeloid leukemia (CML)-committed granulopoietic precursors [colony-forming unit-culture (CFU-C)] has been investigated in a double-layer agar system in which CFU-C growth was stimulated by adherent monocytes. Addition of the prostaglandin synthesis inhibitor indomethacin to the feeder layer significantly increased the number of normal CFU-C, whereas CML CFU-C were unaffected. Exogenous prostaglandin E1 inhibited CML CFU-C growth at concentrations 1000-fold higher than those necessary to produce a similar effect on normal CFU-C. These data point to a lower than normal sensitivity of CML-committed granulopoietic precursors. It is suggested that derangement of the responsiveness of CML cells to prostaglandin regulation may play a role in the pathogenesis of uncontrolled leukemic proliferation.

Expression of HLA class II (DR, DQ) determinants by normal and chronic myeloid leukemia granulocyte/monocyte progenitors.

It has been suggested that the expression of certain HLA class II antigens stemming from three distinct loci (DR, DP, and DQ) is important not only in the regulation of the immune response but also on the response of hemopoietic precursors to factors inhibiting myelopoiesis. Changes in the expression of DR antigens may be involved in the pathogenesis of altered cell proliferation in chronic myeloid leukemia, since they result in decreased sensitivity of the colony forming units, granulocyte-macrophage to prostaglandin E and acidic isoferritins. In studies using monoclonal antibodies against monomorphic DR or DQ determinants, in a complement-dependent cytotoxic assay, it was found that nearly all normal and chronic myeloid leukemia bone marrow colony forming units, granulocyte-macrophage express DR antigens. The dose response curve was similar for both normal and leukemic precursors. Leukemic peripheral blood precursors were more sensitive than were normal peripheral blood precursors. Normal colony forming units, granulocyte-macrophage did not express DQ antigens, whereas these were expressed in varying quantities by leukemic cells. This study shows that, in the patients we studied, leukemic cells express DR antigens in amounts comparable to normal. In addition, varying amounts of DQ antigens may be observed on leukemic but not on normal progenitors, perhaps as a consequence of an increase in the number of antigens also expressed by normal cells, though in an amount below the detection threshold of cytotoxicity techniques.

Peripheral blood and bone marrow immunophenotypic and functional modifications induced in acute leukemia patients treated with interleukin 2: evidence of in vivo lymphokine activated killer cell generation.

The effect of treatment with interleukin 2 (IL2) on the phenotypic and functional immune system of acute leukemia patients was investigated. Fifteen acute myeloid leukemia and acute lymphoid leukemia patients with evidence of persistent disease were further subdivided into two groups according to the percentage of bone marrow (BM) blasts: group a had 6-15% blasts and group b had 30-65%. Following two cycles of IL2 (Glaxo Imb, Geneva, Switzerland) given i.v. by continuous infusion at escalating doses, no major changes in the proportion of CD3-, CD4-, and CD8-positive cells were encountered in the blood or in the marrow of either group of patients. When these could be retested after four cycles of IL2, a significant increase of CD3+ and CD4+ cells was documented in the peripheral blood (PB), as well as a significant increase of CD3+ cells in the BM. Irrespective of the number of cycles administered, the proportion of CD16+ cells increased significantly in the blood in both groups of patients and in the marrow of group a patients only. The expression of CD25 was significantly enhanced in all samples tested. Following IL2 administration, an enhancement of the natural killer compartment was documented. This was consistently more evident in patients with more limited disease. A significant amplification of the in vitro-induced lymphokine-activated killer function was noted in the BM of the treated patients. Furthermore, we documented the presence both in the PB and in the BM of "spontaneous" lymphokine-activated killer cells generated in vivo following IL2 administration. These results demonstrate that in acute leukemia of both myeloid and lymphoid origin, treatment with IL2 is capable of inducing profound immunophenotypic and functional modifications in PB and in BM lymphocytes, particularly in patients with more limited disease. The evidence of the in vivo activation of cytotoxic cells, particularly in the BM, may help to explain the clinical responses preliminarily observed in individual acute leukemia patients.

Has IL2 a role in the management of minimal residual disease for acute leukemia?

Based on pre-clinical findings and on more recent preliminary in vivo data it has been suggested that immunotherapy with Interleukin 2 (IL2) may be employed in the treatment of acute leukemia patients. Here we shall discuss the biological and clinical observations which indicate that this innovative therapeutic approach may play a role in the management of minimal residual disease.

Autologous bone marrow transplantation followed by interleukin-2 in children with advanced leukemia: a pilot study.

In an attempt to prolong disease-free survival in children with acute leukemia, we tested the feasibility of interleukin-2 (IL-2) administration after an autologous bone marrow transplantation (ABMT). We report the clinical and biological data obtained in three children with acute myelocytic leukemia (AML) in second complete remission (CR) and in seven children with acute lymphocytic leukemia (ALL) in second or subsequent CR, who received IL-2 at a median interval of 78 days (range 38-125) from ABMT. Patients were treated with 1-2 cycles of IL-2 given by continuous infusion over a 5-day period using a daily escalating protocol, from 100 micrograms/m2 per day to the maximum tolerated dose, followed after 3 weeks by low-dose IL-2 for 5 days monthly over a 6-h infusion on an out-patient basis. Side effects greater than grade 2 (WHO system), consisting of thrombocytopenia, fever, cutaneous rash, nausea and vomiting, diarrhoea were common during the high-dose IL-2 cycles, but resolved 24-48 h after stopping IL-2. Only one patient developed liver toxicity (grade 3, WHO) on day +3 of the first cycle which prompted us to stop the administration of IL-2. An increase in lymphocytes and eosinophils was also observed. IL-2 treatment was followed by a normalization of NK function and by the generation of a high proportion of endogenous LAK cells. All seven ALL patients relapsed at a median of 5 months (range 1-23). Two AML patients relapsed at 1 and 11 months, while the other is still in continuous CR at 23 months after IL-2 treatment. Our IL-2 schedule for treatment of leukemia in children after ABMT is thus feasible but its efficacy requires further investigation.

Interleukin 2 (IL2) in the management of acute myeloid leukemia: clinical and biological findings.

In this paper we review some of the preclinical findings which have led us to believe that immunotherapy with interleukin 2 (IL2)/lymphokine activated killer (LAK) cells may be a feasible approach in the management of acute myeloid leukemia. The main clinical and biological results so far obtained with IL2 treatment, and the currently ongoing protocols and strategies are discussed.

In-vitro effect of retinoic acid on normal and chronic myeloid leukemia granulopoiesis.

The effect of increasing concentrations of retinoic acid (RA) on the in-vitro proliferation of normal and chronic myeloid leukemia (CML) granulo-monocyte precursors (CFU-GM) was studied. 10(-7)M RA added to semisolid cultures stimulated the growth of day 14 but not of day 7 normal CFU-GM, whereas in CML the growth of both populations was either unchanged or inhibited. Five-day and 10-day preincubation of normal bone marrow cells with RA augmented the number of day 14 CFU-GM (by up to 187% with 10(-6) M RA), whereas there was a marked decrease when CML cells were used. Total cellularity was not much affected, though a slight increase in liquid normal bone marrow cultures and a slight fall in CML cultures could be detected. These data point to a difference in the response to RA of normal and CML precursors. They may offer of preclinical basis for its employment to delay the blastic progression of CML.

Effect of interferon-gamma on HLA class II antigen expression and sensitivity to prostaglandin E1 by normal and leukemic myeloid progenitors.

Chronic myelogenous leukemia (CML) granulo-monocyte committed progenitors (CFU-GM) are markedly less sensitive than normal progenitors to the inhibitory action of prostaglandin E (PGE). This phenomenon has been ascribed to their abnormal expression of HLA class II (mainly DR) determinants. Since interferon gamma (IFN-gamma) is a potent inducer of the expression of HLA class II (DR and to a lesser extent DQ) antigens, we have sought to determine the extent to which this agent can modulate both the antigenic pattern of normal and leukemic progenitors and their sensitivity to PGE 1. 72-h preincubation of normal and CML bone marrow cells with or without IFN-gamma does not significantly change DR and DQ expression by CFU-GM. Pre-incubation for 72 h with and without IFN-gamma produces the following changes in PGE 1 sensitivity: (1) normal CFU-GM lose some sensitivity to PGE 1. This is only marginally counteracted by the presence of IFN-gamma. (2) CML CFU-GM, preincubated with IFN-gamma regain a significant sensitivity to high concentrations of PGE 1. Our data confirm the expression of DR molecules on normal and leukemic progenitors. They also show that, although incubation with IFN-gamma for 72 h in a liquid culture system does not significantly affect the expression of HLA class II molecules by progenitor cells, it may increase their sensitivity to PGE, particularly in the case of CML CFU-GM. Thus expression of HLA class II antigens and sensitivity to PGE may be dissociated.

Expression of HLA class II determinants by normal and chronic myeloid leukemia progenitors.

It has been suggested that the expression of some HLA class II antigens, derived from three loci (DR, DP, DQ) is important in the regulation of both the immune response and the response of haemopoietic progenitors to regulation factors, such as acidic isoferritins (AIF), as well as in the interaction between T lymphocytes and erythroid progenitors (BFU-E). Changes in the expression of class II antigens have been reported on the surface of granulo-monocyte progenitors in chronic myeloid leukemia (CML) and correlated to the abnormal proliferation of such cells. In this study, monoclonal antibodies against DR and DQ monomorphic determinants were used to investigate the expression of these antigens on the surface of normal and CML bone marrow and peripheral blood BFU-E by means of complement mediated cytotoxicity. It was found that most normal and leukemic BFU-E express DR antigens. Antigens density tends to be greater on marrow as opposed to peripheral precursors. In addition, leukemic BFU-E are more sensitive to cytolytic treatment than their normal counterparts. Normal BFU-E do not express detectable amounts of DQ antigens, whereas these are present on a proportion of leukemic BFU-E.

Ontogeny, gene rearrangements and immunophenotype of acute leukaemias.

The progressive availability of more sophisticated technologies has over the last few years allowed a more precise definition of the biological properties of acute leukaemia cells. This, in turn, has enabled to recognize the ontogeny of practically all cases, with particular emphasis to acute lymphoblastic leukaemia, the lineage affiliation of which had, for many years remained uncertain in over half of the cases. Here, we shall review the main achievements, obtained with extensive immunotyping coupled to the use of probes for the immunoglobulin and T-cell receptor genes, which have led to these important clinico-biological acquisitions, and discuss specific situations in which this combined phenotypic and genotypic approach (as well as response to cloned growth factors) may be of particular value.

Induction and Persistence of Complete Remission in a Resistant Acute Myeloid Leukemia Patient after Treatment with Recombinant Interleukin-2.

A complete and persistent clinico-hematologic remission was obtained in an M4 acute myeloid leukemia patient after treatment with recombinant interleukin 2 (rIL2) alone. After two autologous bone-marrow transplantations and in the third relapse with 10% persistent blasts in the marrow, the patient was treated with two intensive courses of rIL2 given by continuous infusion over a period of 13 days. rIL2 administration was accompanied by significant side effects and followed by notable hematological, clinical and immunological modifications. Complete remission was achieved after these two courses and has been maintained with monthly low-dose cycles of rIL2 given on an out-patient basis. Eighteen months after starting treatment with rIL2 the patient is well and in persistent remission.

Hodgkin's Disease in 50 Intravenous Drug Users with HIV-Infection.

Fifty cases of Hodgkin's disease in intravenous drug users (IVDU) have been collected by the Italian Cooperative Group on AIDS-Related Tumors (G.I.C.A.T.). Ninety-two per cent of the patients were males; the median age was 26 years. Persistent generalized lymphadenopathy (PGL) at onset was present in 54% of patients, AIDS in 9%, ARC in 9% while 28% were simply HIV-positive. The initial median absolute number of CD4 lymphocytes was 264/mmc. Opportunistic infections were diagnosed in 20% of patients. In most patients the histological pattern was that of mixed cellularity and lymphocytic depletion (76%). In almost half the initial symptom was a persistent lymph node enlargement due to PGL. In the majority of patients (58%) only a clinical staging and bone marrow biopsy could be performed due to the presence of opportunistic infections, rapid disease progression or refusal of pathologic staging procedures. One patient presented with a Waldeyer's ring involvement, but no other unusual presentations were observed. After MOPP alternated or followed by ABVD or MOPP alone, 15/29 CR (52%) and 14/29 PR (48%) were observed. The median duration of CR was 14 months, while the median survival of CR has not been reached; the median survival of patients treated with chemotherapy with CD4 values at presentation {geq}400/mmc was significantly superior to that in those with CD4 < 400/mmc. The overall median survival was 16 months. Twenty-eight per cent of patients receiving chemotherapy + radiotherapy developed opportunistic as well as non-opportunistic infections (21%). Lethal hepatic toxicity was observed in 2 patients. In conclusion, Hodgkin's disease in IVDU was not found to be associated with unusual presentations, as previously reported for homosexuals. Complete remissions could be achieved in over 50% of patients, but in IVDU non-opportunistic infections in addition to opportunistic infections may also limit treatment administration. The presence of parenchymal functional impairment due to drug abuse, or drug abuse-related infections, such as pneumonia, endocarditis and hepatitis, should lead to the choice of antitumour agents with no or only minor potential liver, lung and cardiac toxicity.

Different kinetic pattern of chronic myeloid leukemia: lymphoblastic and myeloblastic blastic crisis.

Cell kinetic studies were performed in 8 case of lymphoid blastic crisis (BC) of chronic myeloid leukemia at the onset of BC and during subsequent relapses. The results were compared with those found in 7 myeloblastic BC. While in the myeloblastic transformation the labeling index (LI) was always higher in bone marrow than in peripheral blood blasts, suggesting a predominant bone marrow proliferation of the leukemic cells, in the lymphoid transformation a higher LI was often found in peripheral blasts. Moreover, the lymphoblastic transformations were frequently characterized by lymphadenopathy. These findings point to the similarities between lymphoid BC and acute lymphoblastic leukemia, suggesting the possibility that a blastic event may originate in an extramedullary site and that an extramedullary BC is more likely to be lymphoid in nature.

N-ras mutations in myeloid leukemias.

The presence of mutations activating the N-ras gene was investigated by the polymerase chain reaction technique in twenty patients with acute myeloblastic leukemia (AML) at onset and in four patients with Ph1 positive chronic myelogeneous leukemia (CML) either in chronic phase or in blast crisis. Four remission samples and four relapses from the AML cases were also studied. Mutations were found in five out of twenty (25%) untreated AML cases at onset. No mutations were detected in the complete remission samples, two of them with N-ras mutations during the leukemic phase. Two out of the four leukemia relapses were positive for the same N-ras mutation shown at presentation, whereas no new mutations were found in the other two initially negative cases. An N-ras mutation appeared during the blast crisis of one of the four CML, which were all negative during the chronic phase. In conclusion, whereas some data appear to be consistent with a role of the N-ras mutations as initiating events in myeloid leukemias, in other cases N-ras activation seems to represent a factor involved in progression. These data suggest that a partial overlapping between initiation and progression factors could exist in naturally occurring tumors.

Oncology in the nineties: from genes to therapy.

Thanks to the impressive development and application of new sophisticated technologies, the last decade has offered remarkable advances in our understanding of the molecular and biological features of human neoplastic cells. DNA analysis in particular has contributed to the unravelling of some of the possible events which give rise to a transformed cell and which enable it to proliferate indiscriminately and to infiltrate. Cloning techniques which have allowed researchers to obtain and utilize purified molecules represent another milestone. This has opened the era of cytokines and growth factors, both in terms of their possible role in the establishment and/or progression of neoplastic conditions (autocrine/paracrine models) and of their use in clinical practice. Thus, growth factors such as granulocyte-macrophage colony stimulating factors (GM-CSF) and interleukin 3 (IL-3) are currently being employed in the management of cancer patients, mainly to support normal hemopoiesis. Conversely, recombinant interleukin 2 (IL-2) through its unique capacity to generate previously unrecognized cytotoxic activity, lymphokine active killer (LAK), has brought about new and more specific immunotherapeutic strategy. Further therapeutic possibilities will arise from the clinical use of monoclonal antibodies. Finally, the development of genetic engineering has opened the way to the early and revolutionary clinical exploitation of gene therapy; the possibility of utilizing in vivo anti-sense oligonucleotides in an attempt to block the action of specific genes is also being contemplated.(ABSTRACT TRUNCATED AT 250 WORDS)